Table Of ContentUnlocking the Brain
Unlocking the Brain
VOLUME I: CODING
GEORG NORTHOFF
1
3
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Library of Congress Cataloging-in-Publication Data
Northoff , Georg. Unlocking the brain / Georg Northoff .
p. ; cm.
Includes bibliographical references and indexes.
ISBN 978–0–19–982698–8 (alk. paper)—ISBN 978–0–19–982699–5 (alk. paper)
I. Title. [DNLM: 1. Brain—physiology. 2. Brain Mapping—psychology.
3. Cognition—physiology. 4. Neural Pathways—physiology. 5. Neuropsychiatry. WL 335]
612.8—dc23
2012029357
9 8 7 6 5 4 3 2 1
Printed in the United States of America
on acid-free paper
CONTENTS
List of Figures v ii
Preface x i
Introduction x iii
PART I: ENCODING EXTRINSIC STIMULI 1
1. Sparse Coding and Natural Statistics 3
2. Sparse Coding and Neural Inhibition 2 5
3. Sparse Coding on a Regional Level 4 4
PART II: ENCODING INTRINSIC ACTIVITY 6 9
4. Spatial Structure of Intrinsic Activity 7 3
5. Temporal Structure of Intrinsic Activity 9 8
6. Sparse Coding of Intrinsic Activity 1 19
PART III: ENCODING PREDICTIONS 1 43
7. Predictive Coding and Difference-Based Coding 1 45
8. Predictive Coding and Social and Vegetative Statistics 161
9. Predictive Coding and the Brain’s Neuronal Statistics 179
PART IV: ENCODING EXTRINSIC ACTIVITY 2 03
10. Stimulus–Stimulus Interaction and Neural Coding 2 07
11. Rest–Stimulus Interaction and Difference-Based Coding 230
12. Rest–Stimulus Interaction and GABA-ergic Neural Inhibition 256
vi CONTENTS
Epilogue: A Quick Guide to a Future “Theory of Brain Activity” 289
Appendices 2 97
Appendix 1: Neuroempirical Remark: Resting-State Activity versus
Stimulus-Induced Activity—Continuity Hypothesis 299
Appendix 2: Neurotheoretical Remark: Localizationism versus Holism 307
Appendix 3: Neuroepistemological Remark: Brain versus Observer 315
References 3 27
Index 3 53
LIST OF FIGURES
I1-1a and b: Diff erent forms of neural coding xx
I1-2a and b: Intrinsic and extrinsic views of the brain xxviii
I1-3: Overview of the book xxxiii
1 -1: Diff erent coding strategies of sensory input 6
1-2a: Sparse coding: rescaling of responses to dynamic input 8
1-2b: Optimizing information transmission 9
1-3a: Diff erence-based coding as statistically based coding strategy 10
1-3b: Stimulus-based coding as physically based coding strategy 11
1-3c: Temporal diff erence-based coding and “lifetime sparseness” 12
1-3d: Spatial diff erence-based coding and “population sparseness” 12
1-4: Sparse coding of stimulus–stimulus interaction 16
1 -5a: Biophysical-computational constraints and sparse coding 19
1-5b: Reciprocal relationship between sparse coding and local/dense coding 22
1-5c: Species-dependence of the neuron’s physical-computational ranges and
diff erence-based coding 23
2-1: Neural organization and processing in olfactory cortex 28
2-2: Neural inhibition and sparse coding 3 3
2-3a: Neural excitation and inhibition in visual cortex 34
2-3b: Neural excitation and inhibition in visual cortex 35
2-3c: Neural excitation and inhibition in visual cortex 36
2-4a: Excitation-Inhibition balance and sparse coding 39
2-4b and c: Neural inhibition and sparse coding in the spatial domain 41
3-1: Diff erent forms of neural coding on the regional level of neural activity 50
3-2a: Neural processing in perceptual regions during perceptual decision making 53
3-2b: Neural processing in perceptual regions during perceptual decision making 54
3-2c: Neural processing in perceptual regions during perceptual decision making 55
3-3: Diff erence-based coding in sensory cortex 57
3-4a-c: Neural processing in prefrontal regions during perceptual decision making 6 2
3-5: Amplifi cation and condensation hypothesis 66
4-1: Concepts of intrinsic activity, resting-state, and baseline 7 5
4-2: Radial concentric anatomo-spatial organization in subcortical
and cortical regions 7 9
4-3: Diff erent baselines in the brain 83
viii LIST OF FIGURES
4-4a: Resting-state activity in inner and middle ring 8 4
4-4b: Functional connectivity of visual cortex with auditory cortex
and other cortical regions 86
4-5: Diff erent encoding strategies in the relationship between the three rings 91
4-6: Constitution of Spatial Structure by the Brain’s Intrinsic Activity 95
5-1: Relationship between structural and functional connectivity 102
5-2: Diff erence-based coding and functional connectivity 1 07
5 -3: Frequency fl uctuations and functional connectivity 110
5-4: Structure–function relationship and conduction delays 112
5-5: Constitution of temporal structure in the neural activity
of the brain’s intrinsic activity 117
6-1a: Sparse coding in the brain, music, and language 123
6-1b: Sparse coding in the brain, music, and language 124
6-2a: Modulation of resting-state activity by GABA and glutamate Visual cortex 129
6-2b: Modulation of resting-state activity by GABA and glutamate Visual cortex 132
6-2c: Th e fi gure shows the results of a combined fMRI, DTI, and MRS study
with placement of the voxel for MRS in medial prefrontal cortex (mPFC) 133
6-3a: Th e fi gure shows the relationship between GABA, glutamate, neural
inhibition and excitation, and the functional connectivity in the resting state 136
6-3b: Diff erence-based coding of the excitation-inhibition balance
in the resting state 137
7-1: Prediction of stimuli in visual cortex 147
7-2: Diff erence-based coding and predictive coding 152
7-3: Common coding in the generation of predicted and actual input 158
8-1a and b: Social context dependence of neural activity during reward 1 64
8-2a-c: Vegetative context dependence of reward 170
8-3: Constitution of the actual input on the basis of diff erent stimuli 175
8-4: Valuation system and diff erence-based coding 177
9-1a and b: Diff erent forms of anatomical organization and neural coding 182
9-2: Neural overlap between resting-state activity and reward-related activity 186
9-3: Generation of the predicted input 1 92
9-4: Neuronal mechanisms underlying seeking, “wanting,” and value 1 96
10-1a, b, c, and d: Neuronal principles of stimulus–stimulus interaction 2 11
10-2a, b, c, and d: Neuronal mechanisms of “driving and modulatory inputs” 218
10-3a and b: Coding of form and motion 2 24
10-4a and b: Functional segregation and continuum 2 28
11-1a: Local spontaneous variations in ongoing activity of specialized
sensory regions impact perception. Th e upper part illustrates the paradigm 232
11-1b: Nonlinear rest–stimulus interaction in auditory cortex 235
11-2a and b: Inverse eff ectiveness and nonlinear interaction during
rest–stimulus interaction 241
11-3a, b, c, and d: Resting state as “spatiotemporal window of opportunity”
for rest–stimulus interaction 250
12-1a and b: Neurophysiological mechanisms of the gamma cycle 2 60
12-2a: GABAergic and glutamatergic modulation of rest–stimulus interaction 2 69
12-2b: GABAergic and glutamatergic modulation of rest–stimulus interaction 272
12-2c: Intero-and exteroceptive awareness and neural activity in the
cortical midline regions 273
12-2d: Modulation of exteroceptive awareness by GABA-A receptors 274
LIST OF FIGURES ix
12-3a: GABA, glutamate, and rest–stimulus interaction 279
12.3b: GABA, glutamate, and rest–stimulus interaction 282
12-4a and b: Sparse coding and GABA 284
12-4c: Sparse coding and GABA 287
A1-1: “Continuity hypothesis” between resting-state and stimulus-induced activity 3 02
A2-1: Complementarity between holism and localizationism 3 12
A3-1a and b: Brain, concepts, and observer 3 18
